Yes, if it is sized for it. Two 2.1 GPM showers need 4.2 GPM of hot water. With 50°F water coming in and a 120°F setting, that takes a 160,000 BTU condensing gas unit; in the cold North, where winter water arrives near 40°F, 199,000 BTU. A heater sized for one shower will run the second one cold.
A family of four usually peaks at two showers at once, 4.2 GPM. That takes a 160,000 BTU condensing gas unit where winter water comes in at 50°F, and 199,000 BTU where it comes in at 40°F. Tankless heaters are sized by flow at your temperature rise, not by the number of people or bathrooms.
Frequently asked questions
Can a tankless water heater run two showers at once?
Yes, if it is sized for it. Two 2.1 GPM showers need 4.2 GPM of hot water. With 50°F water coming in and a 120°F setting, that takes a 160,000 BTU condensing gas unit; in the cold North, where winter water arrives near 40°F, 199,000 BTU. A heater sized for one shower will run the second one cold.
What size tankless water heater do I need for a family of 4?
A family of four usually peaks at two showers at once, 4.2 GPM. That takes a 160,000 BTU condensing gas unit where winter water comes in at 50°F, and 199,000 BTU where it comes in at 40°F. Tankless heaters are sized by flow at your temperature rise, not by the number of people or bathrooms.
This site uses a small amount of storage so it works, and with your permission, to understand which pages are useful. Read the cookie policy or the privacy policy.